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5 600 x 600 230 x 300 (Periphery) 300 x 400 (Tie Beam)
260
10 (5-10) 625 x 625 400 x 500 (Periphery)
300 x 400 (Tie Beam) 325
(0-5) 750 x 750
15
(10-15) 650 x 650 400 x 650 (Periphery)
300 x 400 (Tie Beam) 270 (5-10) 750 x 750
(0-5) 800 x 800
3x3
5 600 x 600 230 x 300 (Periphery)
300 x 400 (Tie Beam) 260
10 (5-10) 625 x 625 400 x 500 (Periphery)
300 x 400 (Tie Beam) 325
(0-5) 750 x 750
15 (10-15) 650 x 650
400 x 675 (Periphery)
300 x 400 (Tie Beam) 270 (5-10) 750 x 750
(0-5) 800 x 800
Vert
ical
Exte
nsi
on
3x1
5 600 x 600 230 x 300 (Periphery)
300 x 400 (Tie Beam) 260
10 (5-10) 625 x 625 400 x 500 (Periphery)
300 x 400 (Tie Beam) 325
(0-5) 750 x 750
15
(10-15) 650 x 650 400 x 600 (Periphery)
300 x 400 (Tie Beam) 270 (5-10) 750 x 750
(0-5) 800 x 800
3x2
5 600 x 600 230 x 300 (Periphery)
300 x 400 (Tie Beam) 260
10 (5-10) 625 x 625 400 x 500 (Periphery)
300 x 400 (Tie Beam) 325
(0-5) 750 x 750
15
(10-15) 650 x 650 400 x 650 (Periphery)
300 x 400 (Tie Beam) 270 (5-10) 750 x 750
(0-5) 800 x 800
3x3
5 600 x 600 230 x 300 (Periphery)
300 x 400 (Tie Beam) 260
10 (5-10) 625 x 625 400 x 500 (Periphery)
300 x 400 (Tie Beam) 325
(0-5) 750 x 750
15
(10-15) 650 x 650 400 x 700 (Periphery)
300 x 400 (Tie Beam) 270 (5-10) 750 x 750
(0-5) 800 x 800
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
7
Table IV. Model-3: Flat Slab Structure with Drops and Peripheral Beams
No. of Stories
Column Size (mm) Beam Size (mm)
Slab
Thk.(mm)
Drop
Thk. (mm)
Sym
metr
ic
5x5
5 600 x 600
230 x 300 (Periphery)
300 x 400 (Tie Beam) 160 250
10 (5-10) 600 x 600 400 x 575 (Periphery)
300 x 400 (Tie Beam)
200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 600 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
3x7
5 600 x 600
230 x 300 (Periphery) 300 x 400 (Tie Beam)
170 250
10 (5-10) 600 x 600 425 x 650 (Periphery)
300 x 400 (Tie Beam)
200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 600 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
7x3
5 600 x 600
300 x 500 (Periphery)
300 x 400 (Tie Beam) 160 250
10 (5-10) 600 x 600 400 x 700 (Periphery)
300 x 400 (Tie Beam)
210 300
(0-5) 725 x 725
15 (10-15) 625 x 625 450 x 700 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
Asy
mm
etr
ic
Ho
rizo
nta
l E
xte
nsi
on
1x3
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 170 250
10 (5-10) 600 x 600 400 x 625 (Periphery)
300 x 400 (Tie Beam)
200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 650 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
2x3
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 175 250
10 (5-10) 600 x 600 400 x 675 (Periphery)
300 x 400 (Tie Beam) 200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 700 (Periphery)
300 x 400 (Tie Beam) 200 300
(5-10) 725 x 725
(0-5) 800 x 800
3x3
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 180 250
10 (5-10) 600 x 600 400 x 675 (Periphery)
300 x 400 (Tie Beam)
225 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 700 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
Vert
ical
Ex
ten
sion
3x1
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 160 250
10 (5-10) 600 x 600 400 x 625 (Periphery)
300 x 400 (Tie Beam) 200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 650 (Periphery)
300 x 400 (Tie Beam) 200 300
(5-10) 725 x 725
(0-5) 800 x 800
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
8
No. of Stories Column Size (mm) Beam Size (mm)
Slab
Thk.(mm)
Drop
Thk. (mm)
Asy
mm
etr
ic
Vert
ical
Exte
nsi
on
3x2
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 160 250
10 (5-10) 600 x 600 400 x 625 (Periphery)
300 x 400 (Tie Beam)
200 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 675 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
3x3
5 600 x 600
230 x 350 (Periphery)
300 x 400 (Tie Beam) 175 250
10 (5-10) 600 x 600 400 x 575 (Periphery)
300 x 400 (Tie Beam)
210 300
(0-5) 725 x 725
15 (10-15) 625 x 625 400 x 700 (Periphery)
300 x 400 (Tie Beam) (5-10) 725 x 725
(0-5) 800 x 800
IV. RESULTS
The peak responses of base shear & story displacement,
concrete quantity, and steel quantity are obtained for each
case using ETABS and RCDC. The cost of the building for
each case is calculated according to current market rates,
which are shown in Table V. The variation in parameters
listed above are plotted for each case of a building which is shown in Figures 3, 4, 5, 6 & 7, respectively.
Table V. Current Market Rates
Grade of concrete Rate per CMT (Rs.)
M30 5250
M35 5780
M45 6625
Grade of steel Rate per kg (Rs.)
Fe500 62
Figure 3 (a)
For 5-stories, the use of a flat slab system shows a reduction in base shear by an average of 13.15%.
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
9
Figure 3 (b)
For 10-stories, the use of a flat slab system shows a reduction in base shear by an average of -9.11%.
Figure 3 (c)
For 15-stories, the use of a flat slab system shows a reduction in base shear by an average of 1.10%.
Figure 3. Base Shear Values for Buildings with (a) 5-stories, (b) 10-stories, (c) 15-stories
Figure 4 (a)
For 5-stories, model-3 shows an increase in story displacement by an average of 31.26% compared to model-2.
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
10
Figure 4 (b)
For 10-stories, model-3 shows an increase in story displacement by an average of 17.26% compared to model-2.
Figure 4 (c)
For 15-stories, model-3 shows an increase in story displacement by an average of -4.17% compared to model-2.
Figure 4. Maximum Story Displacement Values for Buildings with (a) 5-stories, (b) 10-stories, (c) 15-stories
Figure 5 (a)
For 5 stories, the concrete weight of a flat slab system is reduced by an average of 16.45%.
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
11
Figure 5 (b)
For 10 stories, the concrete weight of a flat slab system is reduced by an average of -1.73%.
Figure 5 (c)
For 15 stories, the concrete weight of a flat slab system is reduced by an average of 5.65%.
Figure 5. Concrete Weight Values for Buildings with (a) 5-stories, (b) 10-stories, (c) 15-stories
Figure 6 (a)
For 5-stories, the weight of steel for a flat slab system is increased by an average of 28.30%.
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
12
Figure 6 (b)
For 10-stories, the weight of steel for a flat slab system is increased by an average of 54.82%.
Figure 6 (c)
For 15-stories, the weight of steel for a flat slab system is increased by an average of 59.48%.
Figure 6. Steel Weight Values for Buildings with (a) 5-stories, (b) 10-stories, (c) 15-stories
Figure 7 (a)
For 5-stories, a flat slab building is costlier than a regular beam-slab building by an average of 14.97%.
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
13
Figure 7 (b)
For 10-stories, a flat slab building is costlier than a regular beam-slab building by an average of 39.64%.
Figure 7 (c)
For 15-stories, a flat slab building is costlier than a regular beam-slab building by an average of 36.73%.
Figure 7. Cost of Buildings with (a) 5-stories, (b) 10-stories, (c) 15-stories
V. CONCLUSION
In this article, 5, 10 & 15 storied, symmetric and
asymmetric buildings are investigated using ETABS and
RCDC according to IS-456 and IS-13920. The results shown
above are evaluated to study the effectiveness of a flat slab
system. From the trend of the results of the present numerical study, the following conclusions can be drawn, It is observed that the base shear is reduced up to 2% by
providing a flat slab system.
The buildings with drop panels show an increase in
maximum story displacement compared to buildings
without drop panels due to reduced floor stiffness.
The concrete weight of flat slab buildings is reduced up to
7% compared to regular beam-slab buildings.
Building with flat slabs shows an increase in steel weight
up to 48% compared to regular beam-slab buildings.
It is observed that flat slab buildings are up to 31%
costlier than regular beam-slab buildings.
The increase in the cost of building with a flat slab
structure as compared to the regular beam-slab structure
is more significant for high-rise buildings as compared to
a low-rise building.
VI. FUTURE SCOPE
The present study considers similar flat slab buildings.
More studies can be done at the various loading stages with
different building parameters or a combination of them,
which will give deeper insight into the efficiency of a flat
slab system. Dynamic analysis can be done, and the capacity
of the system can be studied under time-history analysis or
Dhruv B. Patel et al. / IJCE, 8(8), 1-14, 2021
14
response spectrum analysis. Also, Different design
parameters can be applied with a view to understanding the
behavior of flat slab structures under vertical ground motion.
Certainly, more sophisticated flat slab structures can be
created to quantify the results.
REFERENCES [1] H. J. Shah, Reinforced Concrete., (Advanced Reinforced Concrete),
Ed. 7th, Charotar Publication, 2(2014).
[2] IS 1893-Part 1, Indian Standard Criteria for Earthquake Resistant
Design of Structures. Bureau of Indian Standards, (2016).
[3] IS 456, Indian Standard Plain and Reinforced Concrete-Code of
Practice. Bureau of Indian Standards, (2000).
[4] J. L. Yu, & Y. C. Wang., Punching Shear Behavior and Design of an
Innovative Connection from Steel Tubular Column to Flat Concrete
Slab, Journal of Structural Engineering. 144(9) (2018) 04018144-1 to
04018144-13.
[5] K. Qian, & B. Li., Experimental study of drop-panel effects on the
response of reinforced concrete flat slabs after the loss of corner